Geology. 



Out of 25 species of Crustacea, besides : 



highly organized Tetradecapods and Decapods, the former of which 

 seem to have taken the place of Trilobites. The Tetradecapod described 

 ind figured is the Prosoponiscus problemaiicus first described by Schlo- 

 theim. It has been recently shown by C. Spence Bate to be an Amphi- 

 pod. One species is referred to the Brachyurans. It is the Hemitroch- 

 itcug paradoxus of Schauroth. Dr. Geinitz considers it as related to 

 species of the Pinnotheres family. 



Only three species of Annelids have yet been observed. 



The species of Cephalopods in the Zechstein are three in number. 

 They do not assist in determining the relations of the Permian period ; 

 but there are three species of Pteropods which again point to the Palas- 

 ozoic era. 



Among 25 species of Gasteropods and 50 of Conchifers there are both 

 Palaeozoic and Mesozoic forms ; of the former Straparoltm and Murchi- 

 sonia, and of the latter Schizodus and Pleurophorui have not been ob- 

 served beyond the Zechstein. 



Of Brachiopods, of which 30 species are distinguished, all the leading 

 forms characterizing the Zechstein offer the most indisputable proof of 

 Its Palaeozoic relations. Some of the genera, as Prodvctus and Strnpha- 

 iom,hy their immense numbers of individuals performed the same 

 part in this period as Conchifers dfiring the Mesozoic era. Besides 

 these two genera, Orlkis and Camarophoria belong exclusively to the 

 i alaozoic, while Terebratula and Spirifer occur in later beds. Butjthe 



'rehratula elongaia of the Zechstein 

 vonian form. Moreover, the closest relationship exis 

 ^Phoria Schloiheimi of the Zechstein and Camarophoria Crumena of the 



•rboniferous ; between Spirifer Clannyanus of the Zechstein and Spi- 



'"-"•• -- ,ween .9;jm/fr cmta/w* of the Zech- 



/.c./e/ ui.i„piuuiao UL ni^ r!arboTiifefous J 



5tt/o Credneri of the Zechstein and 



^ytiope near Sunderland. These various equivalent lorr 



fPproach each other, that Davidscm and Kirkby pron* 



Identical.* 



Among the Radiates, Cyatkocrinus 

 ^own as belonging to older formatio 



^^arest to the Palilozoic genus ArchxBocidaris ; a third species, a six- 

 fayed Asterias, is not yet sufficiently known to permit of any conclusion. 



\hirteen corals, all related to Fenestdla, a genus prevalent in the 

 ^^<^hstein, with other species of Stenopora, all point to the Palaeozoic 

 fa. There are 12 species of Foraminifera and 7 of Amorphozoa m the 

 '°'^ '■ - dge of these tribes in the Zechstein is yet very 



